Dear 802.3cu Task Force Participants,
Editor’s comments #77 and #83 argue that it is necessary to put back equation references into the specifications table to achieve clarity.
Proposal for Receiver Sensitivity (RS) Equation References in tables (comments #77, #83)
This is fixing something that has worked perfectly well in 802.3 for the past two decades.
802.3ae TF introduced the concept of OMA (min) minus TDP to enable trade-off between optical TX power and TX penalty. The OMA (min) vs. TDP curve has a hockey stick shape, exactly like the OMA (max) vs. SECQ curve in 802.3cu. Let’s take
a look if the 802.3ae-2002 Standard found it necessary to insert equation references into the spec table to achieve clarity.
No equation references are to be found in the spec table, only numerical values.
Looking in 802.3ba-2010, 802.3bs-2017, 802.3cd-2018, we similarly find no equation references for OMA (min). Numerical values are perfectly clear.
Shockingly, even in 802.3cu, the same hockey stick shaped curve specifications for OMA (min) vs. TDECQ are numerical values, with no need for equation references in the spec table.
Yet in the same Standard, the OMA (max) vs. SECQ hockey stick shaped curves are deemed so different and so complicated that equation references in the spec tables are proposed as the only path to clarity.
A quote from the January presentation proposing the restoration of numerical values to the spec tables, and removal of equation references, is worth repeating.
http://www.ieee802.org/3/cu/public/Jan20/cole_3cu_01b_0120.pdf
If it ain’t broke, don’t fix it.
Thank you
Chris
From: Chris Cole
Sent: Tuesday, April 07, 2020 1:53 PM
To: Peter Stassar <Peter.Stassar@xxxxxxxxxx>; STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: RE: Your presentation on comments #77 and #84
The Editor must have missed the January presentation where the End Users were very clear on their preference.
http://www.ieee802.org/3/cu/public/Jan20/cole_3cu_01b_0120.pdf#page=29
It would sever the IEEE better if we wrote the specifications for them, rather than for our own notion of aesthetics.
Chris
From: Peter Stassar <Peter.Stassar@xxxxxxxxxx>
Sent: Tuesday, April 07, 2020 5:57 AM
To: STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: [802.3_100G-OPTX] Your presentation on comments #77 and #84
Hi Gary and cu colleagues,
I just had a look at your presentation proposing responses to #77 and #84.
While I would agree that the changes agreed in Geneva could cause potential confusing, but at the same time I would agree with Chris, having proposed the changes during the Geneva meeting, that having just the
formula’s would also be confusing.
I believe there is another possibility for addressing the 2 related comments, which is by doing both, namely where we maintain the line in the Table for SECQ up to 1.4 dB with a fixed value and another line for
SECQ higher than 1.4 dB where we show the formula.
Then we don’t need the extensive note.
Furthermore we will also maintain the intent of the change made in D2.0.
There is precedence of dual line entrances in the various Transmitter Tables, where we distinguish between values for power above and below a certain extinction ratio.
Looking forward to our further discussion today.
Kind regards,
Peter
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